Token validation value and record-validation value
CCA uses the token validation value (TVV) to verify that a token is valid.
When a CCA verb generates a key token, it generates a TVV and stores the TVV in bytes 60-63 of the key token. When an application program passes a key token to a verb, CCA checks the TVV. To generate the TVV, CCA performs a twos complement ADD operation (ignoring carries and overflow) on the key token, operating on four bytes at a time, starting with bytes 0-3 and ending with bytes 56-59.
The token-validation value (TVV) is a checksum that helps ensure that an application-program provided fixed-length AES or DES key-token is valid. A TVV is the sum (two’s complement ADD), ignoring carries and overflow, of the key token by operating on 4 bytes at a time, starting with bytes 0 – 3 and ending with bytes 56 – 59. The 4-byte strings are treated as big-endian binary numbers with the high-order byte stored in the lower address. Fixed-length AES and DES key-token bytes 60 – 63 contain the TVV. When an application program supplies a fixed-length AES or DES key-token, the CCA node checks the TVV. When a CCA verb builds a fixed-length AES or DES key-token, it calculates and stores a TVV in the key token.
The record-validation value (RVV) used in AES, DES, and PKA key-storage records is calculated in the same manner as the AES or DES TVV, except that for PKA the last bytes added are always treated as a 4- byte integer. The RVV is the sum of each sequential 4-byte value in the record, except for the four bytes where the RVV itself is stored.